Creation of POSCO was as the result of Government deliberations during the 1960s that self-sufficiency in iron and steel and construction of an integrated steel plant were essential to Korea's economic development.

Construction of the first steel works at Pohang was funded by money received from Japan. This funding was part of a compensation payment received from Japan for its colonial rule of Korea.

In 1986 US Steel entered into a 50:50 joint venture with Pohang Iron and Steel Company to modernize its Pittsburg plant (California) - to supply the facilty with high quality steel. This venture is now known as USS-POSCO Industries, and operates cold rolling and coating plant on the West Coast.

1988: Until the part privatisation, ownership of POSCO was held by the Ministry of Finance and the Government-owned Korea Development Bank.

1988: POSCO's Indian project centres on a $12 billion steel-making complex, which includes a power plant and a port.

2010: According to some analysts, the purchase of Daewoo was at a price significantly above market value.

2012: Capacity expansion project at steel plant in Maharashtra is for reprocessing of austenitic and cold rolled stainless steel at the facility in the Vile-Bhagad and Palasgaon industrial area in Raigad district.

2013: POSCO signed a preliminary agreement in 2010 to build a ~6 million tonne per year steel plant in the southwestern Indian state of Karnataka. POSCO abandoned this project in mid-2013 because of deteriorating market conditions and because of delays in securing mining rights.

2014: According to South Korea's trade ministry, POSCO in mid-2014 signed a Memorandum of Understanding with Chongqing concerning investment in a 3 mt/year steel plant in western China.

2014: POSCO signed MoU to explore new business opportunities with Saudi Arabia’s sovereign fund. These opportunities were at the time thought to be connected with Daewoo International Corporation's plans to build an automobile assembly plant in the Kingdom.

2015: Newly-cancelled $12 billion Odisha project was set up in 2005 - when it was regarded as India's biggest foreign direct investment - but encountered a series of delays. The company waited almost a decade to acquire land for the proposed 12 mt/year steel plant because of opposition from local tribal groups. A mining law enacted in March 2015 would also have required POSCO to purchase a mining license in an auction.

2015: Regarding this DRI plant, Tuwairqi Steel Mills Ltd was a venture between Posco and Saudi Arabia'a Al-Tuwairqi Group which was inaugurated in 2013, but never became operational because of subsequent government disputes concerning the price of natural gas (a principal input for direct reduction of iron ore).

2016: November 2016 talks were reportedly held between POSCO executives and Arrium about the sale of the Whyalla Works, and the search for a viable buyer with long-term commitment.